Caspar Donnison is a second year PhD student in our lab, working on the ADVENT and MAGLUE projects researching the natural capital implications of bioenergy policy, specifically with regards to bioenergy with carbon capture and sequestration (BECCS) technology. He is currently attending a conference in Gothenburg on negative emissions.

Combating climate change is a choice, but we are running low on options

German landscape scattered with windfarms

Standing on the deck of a low-emission ferry to Denmark I see huge offshore wind turbines out at sea, and four large containerships in a line stretched across the horizon. From my high-speed German train yesterday I saw huge sleek wind turbines standing proud on the sunny north German plains, with solar farms dotted here and there, between fields and forest. Many books and popular films describe what ‘the future’ looks like. On this journey it feels like I’ve been looking at the future; many landscapes across Europe are dominated by impressive energy and transport infrastructure.

But big wind turbines, solar farms, and low carbon transport will not be enough to turn the tide on climate change. That is why I am travelling (low carbon, of course) to Gothenburg in Sweden for a conference on ‘Negative Emissions’.

Low carbon travel option across Europe

The idea of negative emissions has come about because action on climate change isn’t going all too well. At the Paris Agreement of 2015 the world’s nations committed to limiting global warming to 2 degrees Celsius, with ambitions to pursue 1.5 degrees if possible. Paris led to the idea of the ‘carbon budget’ – the total volume of carbon dioxide that we cannot emit beyond if we are to keep to those global warming limits. Scientists estimate that we are close to spending that 1.5 degrees budget, with around 20 years left of the 2 degrees budget. That might sound like a fairly long time but we would have to stop emitting carbon entirely once that budget was spent, and carbon-intensive infrastructure that is built today risks a ‘lock in’ to emissions for decades to come. Back to negative emissions…

Backed into a corner with two Unthinkable Choices?

Offshore windfarms enroute to Denmark

If we overshoot the carbon budgets for Paris then we have two options: the first is that we accept the dangerous climate change that would likely result from 2+ degrees of warming, the second is that we deploy technologies which suck carbon out of the atmosphere – ‘negative emissions’ technologies – to keep us back within the 2 degrees of warming. These negative emissions options range from natural solutions such as planting more trees and restoring peatlands (both help store carbon in the soil) to technologies that remove carbon from the air (Direct Air Capture or DAC), increase its absorption by the oceans (‘ocean liming’), and, my area of research: the capture of carbon emitted from bioenergy power stations (bioenergy with

carbon capture and storage, or BECCS).

If we choose to not take action then we risk catastrophic ecosystem collapse, sea level rises and associated mass migration, as well as the increased spread of disease, drought, and crop failure. It probably wouldn’t be the end of the world for us (though it would for some people), but it would most likely be pretty bad. The second option of choosing negative emissions? We don’t really know yet. It partly depends on how much help we need from them. These technologies are mostly untested, with some arguing that they just won’t work, and the limited research into them so far suggests that they will be costly, both financially and environmentally. Untested and expensive, but potentially necessary; that’s why seeing negative emissions as a solution is controversial and why this Gothenburg conference on research into them is so important.

Untested and Expensive, but Potentially Necessary?

A large oil tanker entering Hamburg port

Only one pilot BECCS plant exists globally but the technology is included in almost all of the scientific scenarios that meet carbon budgets for 1.5 degrees, and in many for 2 degrees of warming. BECCS may well achieve significant amounts of negative emissions, but the price is likely to be the impact of significant land-use change to energy crops, which could have negative impacts for food production, water use, biodiversity, and our relationship with the landscape. Not to mention the financial costs of building the BECCS infrastructure.

We don’t yet know enough about the scale required of these technologies – it firstly depends if and by how much we overspend that carbon budget. If we overspend it by 1 tonne of carbon dioxide, I could plant a few trees in my garden and we’d be fine. If we overspend it by a lot we may need to convert a land area the size of India to grow energy crops for BECCS. Research is ongoing as to what the safe or sustainable upper level of BECCS could be. Of course, we may be in a situation where the alternative to costly negative emission technologies – climate collapse – is simply worse, and then we are forced to deploy them, regardless of the cost.

The Third Way

There remains, for now, a Third Way. This is to take significant carbon reduction action now which prevents us from being faced with the Two Unthinkables later. The Third Way will require doing many of the things that we already do, but at a faster rate, and it will require changed lifestyles: significantly reduced meat consumption and air travel. Trends in the growth of renewable energy, battery and storage technology, and individual behaviour are impressive – there are certainly reasons to be positive and hopeful – but we also need to be realistic that the Third Way window is quietly closing on us, and will likely also require some help from negative emissions too. So there is no easy option presented to us.

“Science tells us what we can do; societies tell us what we are allowed to do”

As things stand globally we are on course to miss the Third Way window and overshoot the carbon budgets, implicitly choosing to be left with just two options: climate collapse or negative emission technologies. Through researching negative emission technologies, science now needs to tell us what sort of a choice this is. Societies then need to decide: the Third Way, Negative Emissions, or Climate Collapse.